The major emphasis of research for this period will center on the toxic metabolites produced by the sweet potato (Ipomoea batatas) in response to fungus infections and other injurious stimuli. Work will continue on the characterization of the four lung toxic compounds, previously identified, as well as the hepatotoxic substances. This will include studies on synthesis and biosynthesis of the compounds, factors affecting induced tolerance to lung toxins, pathogenesis of the lung disease, and mechanism of action for the lung toxins. Attempts will be made to develop precise and reliable quantitation analytical methods for each of the toxic metabolites contained in a crude extract mixture. More precise measurements of the toxicity of various synthesized analogs and homologs of the lung toxins will be made. Bioproduction, purification, and mechanism of action studies will continue on at least two mycotoxins of current interest. They are penitrem A, the tremorgenic toxin of Penicillium crustosum, and rubratoxin B, the potent hepatotoxin of P. rubrum. The central nervous system toxicity of penitrem A will be studied in collaboration with Yugoslavian neuropharmacologists. The teratogenicity and embryocidal properties of rubratoxin B also will receive further study.